The present invention relates generally to fastener screws, and more particular to a novel fastener screw having improved installation and holding characteristics and which finds particular application with work pieces made of wood, wood composites and/or plastics.
In many applications where fastener screws are employed to secure work pieces together, such as two or more pieces of wood or the like, it is desired that the screw be driven into the work pieces sufficiently so that top of the screw head is flush with or recessed below the upper surface of the workpiece. For example, in assembling outside wooden decks, it is a common practice to secure the deck planking to support joists or the like with flathead screws so that no part of the screws protrude above the upper deck surface. Where the deck planking is relatively thick and has been treated or impregnated with a weather resistant material, the wood is generally tougher and more resistant to insertion of fastener screws. Thus, a fastener screw capable of penetrating such work pieces and which can be rapidly driven into the work pieces sufficiently to recess the screw head would greatly reduce installation time with attendant cost savings
A problem frequently encountered with known fastener screws in outdoor applications where weather is a factor is that over time the screws may tend to loosen. In applications where the heads of loosened screws may project above a surface over which persons walk, such as an outdoor deck or the like, the protruding screw heads can present significant safety problems, in addition to being obtrusive. Thus, in addition to facilitating rapid installation into one or more work pieces, the fastener screw must be capable of retaining its fastening characteristics over long periods of time without loosening